The Duke and Duchess of Cambridge are thrilled to be expecting their third baby, a sibling for Prince George and Princess Charlotte.
Kate is less than 12 weeks pregnant, with Kensington Palace making the announcement early after the Duchess had to pull out of a public engagement on Monday due to severe morning sickness.
Grandfather the Prince of Wales is said to be “delighted” with the news, as is the Queen and other members of William and Kate’s family.
Kate, who is being cared for at Kensington Palace, is suffering from hyperemesis gravidarum, as she did in her previous pregnancies.
Just weeks ago, the Duchess joked about having a third child while on a tour of Poland and Germany with William, George and Charlotte.
After being given a present designed for newborns while in Warsaw, she laughed and turned to William, saying: ”We will just have to have more babies.”
Kensington Palace said in a statement: “Their Royal Highnesses the Duke and Duchess of Cambridge are very pleased to announce that the Duchess of Cambridge is expecting their third child.
“The Queen and members of both families are delighted with the news.”
Kate had been due to visit the Hornsey Road Children’s Centre in London to hear about the mental health impact of becoming a mother.
Clarence House said of heir to the throne Charles and the Duchess of Cornwall: “They are delighted at the news.”
The Duchess is being cared for at Kensington Palace (Tim Rooke/PA)
The announcement comes as William and Kate are preparing to send their eldest child off to school for the first time.
Four-year-old future king George starts at fee-paying independent school Thomas’s Battersea in south London on Thursday.
The past year has already been one of big changes for the Cambridges.
The news was announced as the royal couple were preparing to send their eldest child, Prince George, off to school for the first time (Jane Barlow/PA)
Their main home is now their Kensington Palace apartment rather than their Norfolk mansion Anmer Hall and William quit his job as a pilot for the East Anglian Air Ambulance in July to become a full-time royal.
The couple’s third child will be born fifth in line to the throne, bumping uncle Prince Harry out of the top five for the first time and into sixth place.
The Prince of Wales is first in line, followed by William, George and two-year-old Charlotte.
Asked for Prime Minister Theresa May’s response to the announcement, a Downing Street spokeswoman said: “It is fantastic news and she passes on her congratulations to the Duke and Duchess of Cambridge.”
Asked about the news as he arrived for a visit in Manchester, Harry said: “Fantastic. Great. Very, very happy.”
And asked how Kate was, he said: “I haven’t seen her for a while but I think she’s OK.”